Supersensitized silver halide emulsions



United States Patent 3 458,318 SUPERSENSITIZED SILVER HALIDE EMULSIONS Dugald A. Brooks, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Aug. 2, 1965, Ser. No. 476,658 Int. Cl. G03c 1/28, 1/10 U.S. Cl. 96-404 19 Claims ABSTRACT OF THE DISCLOSURE Photographic layers containing silver halide bearing:

(1) A cyanine dye having a conjugated chain containing at least three atoms in the chain selected from carbon and nitrogen such that not more than one of said atoms in the chain is nitrogen, or the base from which the said cyanine dye is derived, and

(2) A substituted thiourea in which at least one of the hydrogen atoms on each nitrogen atom of the thiourea molecule is replaced by a 1 to 8 carbon atom hydrocarbon substituent and at least one of the substituents on the said molecule contains an aromatic ring are supersentitized to light in the minus blue or red region of the spectrum and are used advantageously in photography.

This invention is concerned with photography, and more particularly to photographic silver halide containing novel supersensitizing combinations.

It is known in the art of making photographic emulsions that certain dyes of the cyanine class alter the sensitivity of photographic emulsions of the gelatinosilver halide kind, when the dyes are incorporated in the It is therefore, an object of my invention to provide novel photographic layers containing silver halide with a cyanine dye having at least 3 carbon atoms or at least 2 carbon atoms and one nitrogen atom in the conjugated chain, said dye being supersensitized with certain substituted thioureas.

Another object is to provide photographic hydrophilic colloid silver halide emulsions containing a supersensitizing combination of a complex cyanine or an azacyanine dye with certain substituted thioureas.

Another object is to provide photographic hydrophilic colloid silver halide emulsions containing a supersensitizing combination of a carbocyanine, a dicarbocyanine or tricarbocyanine dye with certain substituted thioureas.

Another object is to provide methods for making these supersensitized emulsions.

Still further objects will become evident from a consideration of the following specification and claims.

These and other objects are accomplished according to my invention by the use of photographic layers containing silver halide bearing a:

(l) Cyanine dye having a conjugated chain containing at least three atoms in the chain selected from carbon and nitrogen such that not more than one of said atoms in the chain is nitrogen or the base from which the said cyanine dye is derived, and

(2) A substituted thiourea in which at least one of the hydrogen atoms on each nitrogen atom of the thiourea molecule is replaced by a 1 to 8 carbon atom hydrocarbon substituent and at least one of the substituents on the said molecule contains an aromatic ring.

The cyanine dyes used to advantage according to my invention include those represented by Formula I:

emulsion. It is also known that the sensitization produced by a given dye varies somewhat with the type of emulsion in which the dye is incorporated. Furthermore, the sensitization of a given emulsion by a given dye may be altered by varying the conditions in the emulsion. For example, the sensitization may be increased by increasing the silver ion concentration or decreasing the hydrogen ion concentration (i.e., increasing the alkalinity) or both. Thus, sensitization can be increased by bathing plates coated with a spectrally sensitized emulsion, in water or in aqueous solutions of ammonia. Such a means of altering the sensitivity of a sensitized emulsion by increasing the silver ion concentration and/or by decreasing the hydrogen ion concentration is commonly called hypersensitization. Hypersensitized emulsions have generally poor keeping qualities.

I have now found another means of altering the sensitivity in photographic emulsions containing certain cyanine dyes including complex cyanine, dicarbocyanine, tricarbocyanine and certain azacyanine dyes. Since the conditions in the emulsions, i.e., the hydrogen ion and/ or the silver ion concentration, undergo little or no change in my method, I shall designate my method as a kind of supersensitization.

wherein R and R each represents the same or a different alkyl group substituted or not, such as, methyl, ethyl, propyl, butyl, an alkoxyalkyl (e.g., methoxyethyl, ethoxyethyl, methoxypropyl, etc.), a chloroalkyl (e.g., 2-chloroethyl, 2 chloropropyl, 3 chloropropyl, 4 chlorobutyl, etc.), a hydroxyalkyl (e.g., 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, etc.), a sulfoalkyl (e.g., Z-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, etc.), a carboxyalkyl (e.g., carboxymethyl, 2 carboxyethyl, 4- carboxybutyl, etc); Z and Z each represents the non-metallic atoms necessary to complete a nucleus containing a heterocyclic ring having from 5 to 6 atoms in the heterocyclic ring, in which the hetero atoms are typically nitrogen, sulfur, oxygen, selenium, etc., and the nuclei are typically a thiazole nucleus (e.g., thiazole, 4-methylthiazole, 5- methylthiazole, 4-phenylthiazole, 5-phenylthiazole, 4,5- dimethylthiazole, 4,5 diphenylthiazole, 4 (2 thienyl) thiazole, etc.), a benzothiazole nucleus (e.g., benzothiazole, 4 chlorobenzothiazole, 5 chlorobenzothiazole, 6 chlorobenzothiazole, 7-chlorobenzothiazo1e, 4-methylbenzothiazole, S-methylbenzothiazole, 6-methylbenzothiazole, S-bromobenzothiazole, 6-bromobenzothiazole, 4-phenylbenzothiazole, 5 phenylbenzothiazole, 4 methoxybenzo- (23) 3,3 dimethyl 8,12 diphenoxyoxadicarbocyanine iodide.

(24) 3,3 diethyl 5,5 diphenyloxadicarbocyanine perchlorate.

(25) IO-cyano 3,3 diethyloxadicarbocyanine iodide.

(26) 3,3'-diethyl-10-me'thyloxadicarbocyanine iodide.

(27) 3,3'-diethyl 4,4,5,5' tetraphenylthiazolodicarbocyanine iodide.

(28) 3,3'-diethyl 4,5;4,5' dibenzoseleneadicarbocyanine iodide.

(29) 3,3'-dimethyl 4,5;4,5 dibenzothiadicarbocyanine chloride.

(30) 3,3-diethyl 4,5 ;4,5 dibenzothiadicarbocyanine iodide.

(31) 3,3-diethylthia-l0-azadicarbocyanine iodide.

(32) 3,3-dimethylthia-8-azadicarbocyanine iodide.

(33) l-p-chlorophenyl 3,4 diethyltetrazolothiadicarbocyanine iodide.

(34) 3,3'-dimethyl 9,11 trimethyleneselenadicarbocyanine bromide.

(35) 5,5,6,6'-tetrachloro 1,1',3,3 tetraethylbenzimidazolodicarbocyanine iodide.

(36) 3,3'-diethyloxathiadicarbocyanine iodide.

(37) 3,3 di li-hydroxyethylthiadicarbocyanine bromide.

(38) anhydro 2 [(Z-benzothiazolyl ethohydroxide) methylene]-5-[(1 ethyl 2(1H) quinolylidene)ethylidene]-3-(4-sulfobutyl)-4-thiazolidinone.

(39) anhydro 2 [(Z-benzothiazolyl ethohydroxide) methylene] 5 [(3 ethyl-2(3H)-benzothiazoly1idene) ethylidene]-3-(4-sulf0butyl)-4-thiazolidinone.

(40) anhydro 2 (2-benzothiazolyl ethohydroxide) methylene] 5 [(3 ethyl-2(3H)-benzothiabolylidene) ethylidene] -3- 3-sulfobutyl) -4-thiazolidinone.

(41) anhydro-5,5'-diphenyl 3,3 di(4 sulfobutyl) thiadicarbocyanine hydroxide.

(42) anhydro 3 ethyl-3'-(4-sulfobutyl)thiatricarbocyanine hydroxide.

(43) anhydro 3 ethyl-1'-(4-su1fobutyl)thia-4-carbocyanine hydroxide.

(44) anhydro-3-ethyl-5-phenyl 1' (4 sulfobutyl) thia-4'-carbocyanine hydroxide.

(45) 2-[(2-benzothiazolyl etho p toluenesulfonate)- methylene] 5 [(1,3 diethyl-2(3H)-benzimidazolylidene ethylidene] -3 -ethyl-4-thiazolidinone (46) 3,3'-diphenylthiadicarbocyanine iodide.

(47) 3,3-diphenylthiatricarbocyanine iodide.

(48) 2 [(2 benzothiazolyl ethiodide)methylene]-3- ethyl-5-[ (3 ethyl-2(3H)-benzoxazolylidene)ethylidene]- 4-oxazolidinone.

(49) 2[(2 benzothiazolyl ethiodide)methylene]-3- ethyl-5-[(3 ethyl 2(3H) benzothiazolylidene)-isopropylidene] -4oxazolidinone.

(50) 2-[(3,3-dimethyl 3H indol-2-yl ethiodide)methylene]-3-ethyl-5-[ (3-ethyl 2(3H) benzothiazolylidene) ethylidene] -4-thiazolidinone.

(51) 2-[ (2-benzothiazolyl ethiodide) methylene1-3-ethy1-5-[(l-ethyl 3,3 dimethyl-3H-indol-2(1H)-ylidene)- ethylidene] -4-thiazolidinone.

(52) 2-[5-(2 benzothiazolyl e'thiodide)-2,4-pentadienylidene]-1-ethyl-4( [(3 ethyl-2(3H)-benzoxazolylidene)- ethylidene]-3-phenylimidazolidin-5-one.

(53) 3,3-diethylselenadicarbocyanine iodide.

The substituted thioureas used to advantage for supersensitizing the dyes of Formula I and the base from which the said dyes are derived, include those represented by the formula:

II R

wherein R and R each represent the same or different member, such as, hydrogen, a lower alkyl group (e.g.,

methyl, ethyl, propyl, butyl, etc.), an aralkyl group (e.g., benzyl, methylbenzyl, phenethyl, etc.), an aryl group (e.g., phenyl, tolyl, ethylphenyl, etc.); and R and R each represents the same or a dilferent group, such as, a lower alkyl group (e.g., methyl, ethyl, propyl, butyl, etc.), and an aryl group (e.g. phenyl, tolyl, ethylphenyl, etc.), such that at least one of the groups R, R R and R contains an aryl ring.

Typical examples of my substituted thioureas used to advantage according to my invention include the followmg:

A--Tetrabenzylthiourea B-N,N'-diethyl-N,Ndiphenylthiourea CN,N,N-tribenzyl-N'-phenylthiourea DN,N'-di-benzy1-N,N'diphenylthiourea EN,N-dibenzyl-N'-ethyl-N-phenylthiourea FN-benzyl-N,N'-diethyl-N-phenylthiourea GN-ethyl-N,N,N-triphenylthiourea HTetraphenylthiourea I--N-methyl-N'phenethylthiourea JN,N-diethyl-N',N'-diphenylthiourea KN,N-diphenyl-N,N-ethylenethiourea My supersensitizing combinations are used to advantage to supersensitize photographic silver halide layers in which the silver halide forms the layer or in which silver halide grains are dispersed in a hydrophilic colloid binder such as, gelatin or any of the other binders used in photography including albumin, agar-agar, gum arabic, alginic acid, etc., and synthetic hydrophilic resins, e.g., polyvinyl alcohol, polyvinyl pyrrolidone, cellulose ethers, partially hydrolyzed cellulose acetate, etc. The silver halides used are silver bromide, silver bromoiodide, silver iodide, silver bromochlorobromide, silver chloride, silver chlorobromide, etc.

The following examples will still further illustrate my invention:

Example 1 A simple gelatino-silver bromoiodide emulsion of the type described by Trivelli and Smith, Phot. Journal, vol. 79, 330 (1939) was prepared. To separate portions of the melted emulsion were added the individual representative dyes of my invention, each dissolved in an appropriate solvent, and then the tetrabenzylthiourea was added at 0.15 g./mole of silver halide from methanol solution. A control emulsion was prepared for each dye but without the tetrabenzylthiourea. Each portion of the emulsion was digested at 50 C. for 10 minutes and coated on a cellulose acetate film support. A strip of each coating was exposed on an intensity scale sensitometer with light modulated with a. Wratten #15 filter, and then processed for 3 minutes in a developer having the formula:

G. P-rnethylaminophenol sulfate 2.0 Sodium sulfite, desiccated 90.0 Hydroquinone 8.0 Sodium carbonate, monohydrated 52.5 Potassium bromide 5.0

Water to make 1 liter.

followed by fixing in a conventional sodium thiosulfate fixing bath, washing and drying. From densitometric measurements of the developed images, the relative speed, fog and gamma values were determined. The relative speed values are inversely proportional to the exposure necessary to give a density of 0.3 above fog (density). The following table lists these data.

TABLE I With 0.15 g. of tetra- Without benzylthiom'ea per tetrabenzylthiourea mole of silver halide Dye and cone. Rel. Rel. g./mole speed 7 Fog speed 7 Fog 045 100 1. 72 07 195 1. 38 06 075 100 1. 52 O6 118 1. 25 06 030 100 1. 32 10 191 1.60 09 045 100 1. 62 06 132 1.30 06 025 100 2. 08 07 166 1. 90 07 020 100 1. 80 06 417 1. 77 06 025 100 1. 94 06 575 2.06 06 030 100 1. 28 06 282 1. 58 06 080 100 1. 26 11 347 2. 46 08 005 100 3. 52 06 151 3. 50 07 041 100 1. 92 06 159 1. 93 06 020 100 1. 95 06 112 1. 88 06 041 100 1. 91 10 115 1. 88 07 041 100 1. 46 07 148 1. 48 06 040 100 2.06 07 145 1. 98 06 040 100 1. 62 13 182 1. 61 07 040 100 2. 30 06 145 1. 62 07 040 100 2. 04 06 162 1. 77 06 040 100 2. 06 123 1. 75 06 010 100 1. 61 06 141 1. 50 06 030 100 2. 86 08 162 3. 12 10 030 100 3. 52 08 525 2. 26 08 015 100 2. 20 08 214 2. 68 08 040 100 2. 88 08 309 2. 50 10 040 100 3. 08 08 347 2. 34 09 040 100 2. 86 09 276 1. 89 10 015 100 3. 44 10 214 2. 80 09 004 100 3. 14 10 324 3. 28 09 004 100 3. 62 08 436 3. 34 08 015 100 3. 00 10 1100 2. 58 08 066 100 2. 30 04 347 1. 96 05 066 100 2. 44 05 776 2. 20 05 083 100 2. 38 06 166 1. 30 06 066 100 2. 48 09 380 2. 46 06 083 100 2. 60 09 126 2.04 0G 066 100 1. 45 06 276 1. 57 05 066 100 1. 92 04 151 2. 30 04 066 100 0. 55 07 661 1. 64 06 083 100 1. 52 08 155 1. 18 09 050 100 1. 53 08 166 1. 1O 36 066 100 1. 54 04 132 1. 42 05 066 100 1. 07 04 126 1. 40 04 020 100 0. 98 04 575 0.82 04 010 100 1. 10 04 145 0. 92 04 043 100 1. 21 04 112 0. 94 04 043 100 1. 28 03 145 0. 77 03 066 100 1. 32 06 276 1. 01 04 066 100 1. 14 06 224 0. 89 04 033 100 1. 23 04 347 1. 37 04 In every instance the emulsion containing my supersensitizing combinations had substantially higher relative speeds than the corresponding emulsion containing no tetrabenzylthiourea. Speed increases of up to 11 times the control emulsion speeds are shown.

The following example illustrates the method used to determine the optimum amount of tetrabenzylthiourea to use in my supersensitizing combination.

Example 2 A simple gelatino-silver bromoiodide emulsion was made as in Example 1. This was divided into 3 portions and the indicated amount of Dye 1 and tetrabenzylthiourea were added to these portions which were then digested, coated, exposed and processed as described in Example 1. The relative speeds, gamma and fog values are tabulated as follows:

TABLE II Dye and supersensitizer Rel. cone, gJmole of silver Speed halide -y Fog 8 and 38 with and without tetrabenzylthiourea. The resulting relative speed, gamma and fog values obtained are given below.

Example 1 was repeated using the dyes and substituted thioureas (supersensitizers) indicated in Table IV. Each emulsion coating was exposed on an intensity scale sensitometer with light modulated with a Wratten #16 filter instead of the #15 filter used in Example 1.

TABLE IV Dye and supersensitizer cone, g./mole of silver Rel.

halide Speed 1 Fog In every instance the emulsion containing my supersensitizing combinations had substantially higher relative speeds than the corresponding emulsion containing no substituted thiourea. Relative speed increases up to 6 times the control are shown.

Example 5 Example 1 was repeated using the dyes and substituted thioureas (supersensitizers) indicated in Table V. Each emulsion coating was exposed on an intensity scale sensitometer with light modulated with a Wratten #16 filter instead of the #15 used in Example 1.

The dyes used in my supersensitizing combinations are known. Numerous references are known showing the preparation of carbocyanine, dicarbocyanine, tricarbocyanine and azaca-rbocyanine dyes. Complex cyanine dyes, for example, are described in patents, such as 2,388,963, 2,430,295, 2,440,119, 2,442,710, 2,454,629, 2,504,468, 2,535,982, 2,535,993, 2,656,351, etc.

Dyes, such as, dye' No. 5 are prepared to advantage by reacting approximately equimolar amounts of 2,4,5-trimethylpyrylium salt and 3-ethyl-2-ethylthiobenzothiazolium ethyl sulfate. The product of this reaction is reacted with an equimolar amount of 2-ethyl-2-ethylthiobenzothiazolium ethyl sulfate to produce the dye.

Dyes, such as dye No. 5 are prepared to advantage by by reacting equimolar amounts of 2,4,6-trimethyl pyrylium salt and 2-(2-acetanilidovinyl)-3-ethylbenzothiazolium iodide. The product of this reaction is then reacted with 3-ethyl-2-ethylthiobenzothiazolium ethyl sulfate to give the dye.

The compounds of Formula II are known and are readily prepared by methods known in the art. Many of the compounds are available.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention and described hereinabove and as defined in the appended claims.

I claim:

1. A light-sensitive layer containing silver halide grains containing:

(1) a dye selected from the class consisting of (a) a cyanine dye having the formula:

wherein R represents an alkyl group; R represents an alkyl group; d represents an integer of from 1 to (1) a dye selected from the class consisting of (a) a cyanine dye having the formula:

2; n represents an integer of from 1 to 3; p represents an integer of from 1 to 2; x represents an integer of from 1 to 2; represents an integer of from 1 to 2; j represents an integer of from 1 to 2; L, L L and L each represents a member selected from the class consisting of a methine group and the nitrogen atom such that not more than one of the said L groups represents the nitrogen atom; L and L each represents the :CH- group and L represents the =CH- group or the :CR group where R is B-indolyl; A represents a heterocyclic nucleus selected from the class consisting of a 4- thiazolidinone nucleus, a 4-imidazolidinone nucleus, a 2-imidazolin-4-one nucleus, a 4-oxazolidinone nucleus, the 1,3-dithiolan-4-one nucleus, the imidazo [1,2-a]pyridinone nucleus, and X- represents an acid anion; Z and Z each represents the non-metallic atoms necessary to complete a nucleus containing a heterocyclic ring having from 5 to 6 atoms in the said ring; and (b) an unquaternized form of said cyanine dye; and

(2) a substituted thiourea in which at least one of the hydrogen atoms on each nitrogen atom of the thiourea molecule is replaced by a substituent and at least one of the substituents on the said molecule contains an aromatic ring.

2. A light-sensitive layer of claim 1 in which the substituted thiourea has the formula:

wherein R and R each represents a member selected from the class consisting of hydrogen, a lower alkyl group, an aralkyl group and an aryl group; R and R each represents a member selected from the class consisting of a lower alkyl group, an aralkyl group and an aryl group, such that at least one of the groups R, R R and R' contains an aryl ring.

3. A light-sensitive layer of claim 1 in which the substituted thiourea is tetrabenzylthiourea.

4. A light-sensitive layer of claim 1 in which the substituted thiourea is N,N'-diethyl-N,N'-diphenylthiourea.

5. A light-sensitive layer of claim 1 in which the substituted thiourea is N,N,N'-tribenzyl-N-phenylthiourea.

6. A light-sensitive layer of claim 1 in which the substituted thiourea is N,N,dibenzyl-N,N'-diphenylthiourea.

7. A light-sensitive layer of claim 1 in which the subwherein R represents an alkyl group; R represents an alkyl group; d represents an integer of from 1 to 2; n represents an integer of from 1 to 3; p represents an integer of from 1 to 2; x represents an integer of from 1 to 2; y represents an integer of from 1 to 2; i represents an integer of from 1 to 2; L, L L and L each represents a member selected from the class consisting of a methine group and the nitrogen atom such that not more than one of the said L groups represents the nitrogen atom; L, and L each represents the =CH group and L represents the =CH group or the =CR ground where R is B-indolyl; A represents a heterocyclic nucleus selected from the class consisting of a 4-thiazolidinone nucleus, a 4-imidazolidinone nucleus, a Z-imidazolidinone nucleus, a 2-imidazoline-4-one nucleus, a 4-oxazolidinone nucleus, the 1,3-dithiolan-4-0ne nucleus, the imidazo [,1,2a] pyridinone nucleus, and X represents an acid anion; Z and Z each represents the non-metallic atoms necessary to complete a 5 to 6 membered heterocyclic nucleus selectedfrom the class consisting of a thiazole nucleus, at benzothiazole nucleus, a napththothiazole nucleus, a 6,7,8,9-tetrahydronaphthothiazole nucleus, an oxazole nucleus, a benzoxazole nucleus, a naphthoazole nucleus, a selenazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a thiazoline nucleus, a 2-quanoline nucleus, a 4-quinoline nucleus, a l-isoquinoline nucleus, a 2- pyridine nucleus, a 4-pyridine nucleus, an imidazole nucleus, at benzimidazole nucleus, a naphthimidazole nucleus, a 3,3-dialkyl(3H)indole nucleus and a tetrazole nucleus; and (b) an unquaternated form of said cyanine dye; and (2) a substituted thiourea having the formula:

wherein R and R each represents a member selected from the class consisting of hydrogen, a lower alkyl group, an aralkyl group and an alkyl group; R and R" each represents a member selected from the class consisting of a lower alkyl group, an aralkyl group and an aryl group, such that at least one of the groups R R R and R contains an aryl ring. 13. A photographic hydrophilic colloid silver halide emulsion layer containing a supersensitizing combination of:

(1) a dye selected from the class consisting of a cyanine dye and an unquaterm'zed form of said cyanine dye, said dye having a conjugated chain containing at least three atoms in the chain selected from the class consisting of carbon and nitrogen such that not more than one of said atoms in the chain is nitrogen and such that the said chain contains an odd number of from 3 to 11 carbon atoms, said conjugated chain terminating at each end in basic heterocyclic nuclei having from 5 to 6 atoms in the heterocyclic ring selected from the class consisting of a thiazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a 6,7,8,9tetrahydronaphthothiazole nucleus, an oxazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a selenazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a thiazoline nucleus, a 2-quinoline nucleus, a 4-quinoline nucleus, a l-isoquinoline nucleus, a 2-pyridine nucleus, a 4-pyridine nucleus, an imidazole nucleus, a benzimidazole nucleus, a napthimidazole nucleus, a 3,3-dialky1- (3H)indole nucleus and a tetrazole nucleus, and (2) a substituted thiourea in which at least one of the hydrogen atoms on each nitrogen atom of the thiourea molecule is replaced by a hydrocarbon substituent and at least one of the substituents on the said molecule contains an aromatic ring. 14. An emulsion layer of claim 13 in which the hydrophilic colloid is gelatin.

15. A light-sensitive gelatino silver halide emulsion containing a supersensitizing combination of tetrabenzyl- 12 thio urea and 3,3-diethyl-4,5; 4',5'-dibenzothiadicarbocyanine iodide.

16. A light-sensitive gelatino silver halide emulsion containing a supersensitizing combination of tetrabenzylthio urea and 3,3'-dimethylthio-8-azadioarbocyanine iodide.

17. A light-sensitive gelatino silver halide emulsion containing a supersensitizing combination of tetrabenzylthio urea and anhydro-2-[(Z-benzothiazolyl etho hydroxide)methylene]-5-[ (3 ethyl-2(3H)benzothiazolylidine)- ethylid ene] -3- (3 -sulfobutyl) -4-thiazolidin-one.

18. A light-sensitive gelatino silver halide emulsion containing N,N,N'-tribenzyl-N'-phenylthiourea and 3,3- diethyloxathiadicarbocyanine iodide.

19. A light-sensitive gelatino silver halide emulsion containing N,N'-dibenzyl-N,N'-diphenylthiourea and 3,3- diethyloxathiadicarbocyanine.

' References Cited UNITED STATES PATENTS 3,287,136 11/1966 McBride 96106 3,155,514 11/1964 Blake 96107 3,364,032 1/1968 Jones 96107 J. TRAVIS BROWN, Primary Examiner.

U.S. C1. X.R. 96105, 106

Patent No. 3, +58,3l8 Dated July 29, l969 lnv nt fl Dueald A. Brooks 1' appears in the above-identified patent It is certified that erro rected as shown below:

and that said Letters Patent are hereby cor Column l0, lines 20-25, in the structural formula,

that part of the structure that reads :L should read (--L and insert in its place "Z-quanolinef and and in lines 60 through tructure that line 38 delete the word "ground" ---group---; line 53, delete the term insert in its place ----2--quinoline---; 6 in the structural formula, that part of the s should read R reads R SIGNED MID SEALED MAY 1 21970 (SEAL) Attcst: Edward M. Fletcher, Ir. ILLIAM E, lsgguy -ia Allfisting Officer f Patnnts 

